We are transferring 3 million archived invoices from SFTP server to our first-ever SharePoint Online Record Center. Moving the files into SharePoint is not the problem, getting the files folder-partitioned and crawled by Search is. It will take too many months to process all 3 million through the Drop Off Library/Content Organizer at the apparent throttled-rate of 5-6000 files per day. The PDFs are uniformly small (60-180 KB); and this Record Center is dedicated to a single content type: Invoices. How should we do this at this scale? Thank you.